An electronic brake system (EBS) utilizes a hydraulic control unit (HCU) to perform various functions within the brake system. The Federal Motor Vehicle Safety Standards (FMVSS) and the Economic Commission of Europe (ECE) standards require various safety requirements be fulfilled to ensure proper functionality of the EBS. One such standard is a required check by the HCU every ignition cycle that a pump motor for the EBS is operational.
To perform the pump check the HCU applies current to the motor for a period of time, stops the application of current to the motor, then measures the voltage generated by the motor as it continues to rotate, i.e. acts as a generator when current is no longer being applied. As such, the motor must reach sufficient speed to generate measureable voltage when no longer receiving power from the HCU. Measureable voltage requires the output from the pump motor be of a sufficient level and a sufficient duration that the HCU can obtain the data.
However, in order to reach rotational speed and duration sufficient to generate measureable voltage the pump motor creates undesirable NVH that can be heard or felt from within the passenger compartment of the vehicle. Various methods of masking the NVH created by the pump check are used to minimize the passengers notice.
The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.